# {a | a>=0 }
D 1
2 3
1 0 1
1 1 0
# {a | a<=0}
D 1
2 3
1 -1 0
1 0 1
F 2

DomSimplify[readDom["{a | a>=0 }"],
            readDom["{a | a<=0}"]]
(*answer =
domain[1, {a},
       {pol[2, 2, 0, 0,
            {{1, 0, 1}, {1, 1, 0}},
            {{1, 0, 1}, {1, 1, 0}}
           ]
       }
      ]
{a|a>=0}
*)
